Geometry controls diffusive target encounters and escape in tubular structures

Fuente: arXiv
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Auteurs principaux: Kim, Junyeong L., Brown, Aidan I.
Format: Preprint
Publié: 2024
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author Kim, Junyeong L.
Brown, Aidan I.
author_facet Kim, Junyeong L.
Brown, Aidan I.
contents The endoplasmic reticulum (ER) is a network of sheet-like and tubular structures that spans much of a cell and contains molecules undergoing diffusive searches for targets, such as unfolded proteins searching for chaperones and recently-folded proteins searching for export sites. By applying a Brownian dynamics algorithm to simulate molecule diffusion, we describe how ER tube geometry influences whether a searcher will encounter a nearby target or instead diffuse away to a region near to a distinct target, as well as the timescale of successful searches. We find that targets are more likely to be found for longer and narrower tubes, and larger targets, and that search in the tube volume is more sensitive to the search geometry compared to search on the tube surface. Our results suggest ER proteins searching for low-density targets in the membrane and the lumen are very likely to encounter the nearest target before diffusing to the vicinity of another target. Our results have implications for the design of target search simulations and calculations and interpretation of molecular trajectories on the ER network, as well as other organelles with tubular geometry.
format Preprint
id arxiv_https___arxiv_org_abs_2402_03059
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Geometry controls diffusive target encounters and escape in tubular structures
Kim, Junyeong L.
Brown, Aidan I.
Biological Physics
Soft Condensed Matter
Statistical Mechanics
Subcellular Processes
The endoplasmic reticulum (ER) is a network of sheet-like and tubular structures that spans much of a cell and contains molecules undergoing diffusive searches for targets, such as unfolded proteins searching for chaperones and recently-folded proteins searching for export sites. By applying a Brownian dynamics algorithm to simulate molecule diffusion, we describe how ER tube geometry influences whether a searcher will encounter a nearby target or instead diffuse away to a region near to a distinct target, as well as the timescale of successful searches. We find that targets are more likely to be found for longer and narrower tubes, and larger targets, and that search in the tube volume is more sensitive to the search geometry compared to search on the tube surface. Our results suggest ER proteins searching for low-density targets in the membrane and the lumen are very likely to encounter the nearest target before diffusing to the vicinity of another target. Our results have implications for the design of target search simulations and calculations and interpretation of molecular trajectories on the ER network, as well as other organelles with tubular geometry.
title Geometry controls diffusive target encounters and escape in tubular structures
topic Biological Physics
Soft Condensed Matter
Statistical Mechanics
Subcellular Processes
url https://arxiv.org/abs/2402.03059